Best grit for 8Cr13MoV. . . Cliff Stamp

J

Jamesh Bond

Joined
Jan 14, 2007
Messages
1,760
I just got a new Meadowlark and I am curious as to what the best grit would be to finish the edge for optimum performance and retention for the steel.

Cliff, I know you have a lot of knowledge for this type of thing. I like your knife tests, been following for years.

This question, or course, is not limited to Cliff.
Thanks in advance!
 
To save Cliff a post and you some time:

"What are you cutting and how are you cutting it?"
 
I realize the medium makes a difference in how to refine the edge, but what I am after is what coarseness to leave the edge to let the steel's properties work the best, regardless of what I am cutting.
 
This is one of the few steels in modern knives which is designed as an actual knife steel. That is to say it has the ability to take a very sharp edge and the properties to hold it and Spyderco is running it nice and hard. Considering its purpose I would run it with a high polish and use it for push cutting. For an aggressive slicer I would use a much more coarse finish on a much higher carbide steel, D2 or similar.

-Cliff
 
Thank you Cliff, for your prompt reply.
I wonder why so many companies are using inferior steels for expensive knives when Byrd can offer this at such a ridiculousy low price!
 
Jamesh Bond,
I believe that's the second time you have complained about the use of "inferior steels" in your posts. (IIRC you also made the same complaint in your Cold Steel post about their use of 1085 for their large chopper blades. Correct me if my aging brain is playing tricks on me.)

Could you clarify and tell us exactly what you mean by "inferior steel"? What company, what knife, what steel?
 
Certainly:

By "inferior steel," I refer to steel with too little carbon in it to make a blade that has the properties of edge retention, sharpness, durability, etc.

For various reasons, I won't go into making a list of knives and companies.

Some low carbon steels are 420, 420j2 (crap), 420HC, aus-4, aus-6. I consider these inferior and avoid them when I can, tho I have a pretty good knife in aus-4. It just doesn't stay sharp.

Some common high carbons are 440c, aus-8, 154cm, s30v, D2, 5160, 1095. I consider these good to excellent, in no particular order.

Here is a great link to Cliff's site about steels.
www.cutleryscience.com/reviews/blade_materials.html
 
well, I can't think of a reason to use 420J2 over 12C27

*replaces all of Thom's M2 with 303 and skitters away*
 
Jamesh Bond said:
Certainly:

By "inferior steel," I refer to steel with too little carbon in it to make a blade that has the properties of edge retention, sharpness, durability, etc.

For various reasons, I won't go into making a list of knives and companies.

Some low carbon steels are 420, 420j2 (crap), 420HC, aus-4, aus-6. I consider these inferior and avoid them when I can, tho I have a pretty good knife in aus-4. It just doesn't stay sharp.

Some common high carbons are 440c, aus-8, 154cm, s30v, D2, 5160, 1095. I consider these good to excellent, in no particular order.

Here is a great link to Cliff's site about steels.
www.cutleryscience.com/reviews/blade_materials.html
Click to expand...

The steels you consider "good" are indeed excellent for edge holding.

I would ask you to consider that edge holding is not always the highest priority in a blade steel. Large heavy blades that are meant for heavy impacts can benefit from the toughness of some of the steels you say we must avoid. There is a current thread on the knife review forum about a knife seemed to be made for chopping based on the blade design. But it was made from 440C and when used for chopping, it broke into chunks. (Pricey blade, too.) For that blade, 440C was an inferior steel. The knife would have benefitted from using AUS4 or 440A because they are tougher. They could have used a carbon steel, but apparently corrosion resistance was one of their design parameters.

The reason I asked you to name examples was because, while 440A might not have the best properties for an EDC, it works fine for a big tough stainless chopping blade or perhaps for a river knife that requires extreme corrosion resistance. So I wanted to see what exactly you were decrying. From your choice of steels, you evidently only prize edge holding. Nothing wrong with that. It is one of my parameters also. But a blanket statement about inferior steels can easily be misinterpreted.

I've gotten in trouble with ThomBrogan before for quoting him, but I'll try it again with fingers crossed. "There are no inferior steels."

There are inappropriate uses for steels.

A more complete statement of your original complaint might be "I wish that more knife companies would use steels with excellent edge retention in their knives that are designed with edge retention as a principal design parameter." And there are indeed some companies that fail in this regard.

Note: 8Cr13MoV is actually pretty close to AUS8 in composition and there are a number of companies who offer AUS8 blades. But, I believe the reason the Byrd line is so inexpensive is that it is made in China with less expensive labor, not merely that it uses a less expensive version of AUS8. (Yes, I understand that Spyderco does a bloody good job of it. And no, I do not wish to discuss the pros and cons of knives made in China.)

second note: I am aware of Cliff's site and have read many of his offerings. But thanks for the link.
 
Knarfeng,
The word "inferior" means "lower than a given reference point." There ARE inferior steels. This is not an opinion. It is a fact based on the definition of the word.

You are obviously highly knowledgable, so why the need for all the overexplaination? I didn't want to go into painful detail because, you are right, there are appropriate and inppropriate uses for steels. I am more than aware of these. I wanted to avoid having to cite an almost infinite number of combinations, opinions, and factors on the matter just to state what I meant. I find it unneccessary be required to go into ridiculous detail overexplaining something most people already understand.

To sum it up, this is what I meant:
Some knife companies are using steels grossly unsuited for the intended use and class of knives they are selling. There are many other steel options for the same knives that would outperform in every way, most notably in edge holding. This makes the steel for the use it was intended INFERIOR to the potential better steel.

You requested an example: CRKT. Are you really telling me that 420j2 in a hunting knife or pocket knife is not inferior to aus-8 or s30v?

Look at the high carbon steels I listed again. Most do offer great edge holding ability, some, not so much. That list does not imply I ONLY value edge holding ability. But without an edge, a knife isn't a knife. Without the right steel, an edge isn't a cutting edge.

BTW, the Cold Steel post about 1085 large chopper blades was not mine. I'm not sure I've even read it.

Regards.
 
Thanks for reminding me.
That post says nothing about any specific steel. The thread was someone else's, and if I recall correctly, they were discussing steels that they felt were inappropriate. I posted that unspecific response to agree with some points that lots of knives have inappropriate steels for their use.
 
this is the thread http://www.bladeforums.com/forums/showthread.php?t=446001
it was about SK5

I take my Cara Cara up to as high a polish I can get (ultra fine spyderco then strop w/ chromium oxide) but it is combo edge and I use the serrations for aggressive slicing. I polish all my plain edges, I also carry a Leatherman with a serrated blade and a diamond file which can put a rough edge on a knife quickly.
 
My meadowlark was shaving sharp when i got it. I put some microbevels on it with a ceramic dog bone to refine and clean up the edge, then stropped it on a piece of leather with superfine abrasive compound on it. I'm gonna see how long this polished edge remains usable until it's dull, then I'm going to resharpen it with a fine DMT then finish with mild stropping it for a slicing edge to compare.
I found that aus-8 and 440a won't hold the razor fine edge I like for very long, and the knife won't cut much when this happens. I compromise by leaving the edge fairly coarse, to where it cuts paper but barely shaves, then the knife remains usable for much longer.
 
Jamesh Bond said:
To sum it up, this is what I meant:
Some knife companies are using steels grossly unsuited for the intended use and class of knives they are selling. There are many other steel options for the same knives that would outperform in every way, most notably in edge holding. This makes the steel for the use it was intended INFERIOR to the potential better steel.

You requested an example: CRKT. Are you really telling me that 420j2 in a hunting knife or pocket knife is not inferior to aus-8 or s30v?QUOTE]

We agree both in your summary statement and the example you give. 420j2 is an inappropriate choice for such a knife.

I was just wondering what your thinking was after reading the Cold Steel SK5 post and your comment earlier in this thread about the 8Cr13MoV.

Just checking.

Thanks,
knarfeng
Click to expand...
 
No question. Just yammering on too long.

I do that sometimes.

Edited to add:
You had asked me why I asked the original question. I was telling you why I asked it.
 
Jamesh Bond said:
I found that aus-8 and 440a won't hold the razor fine edge I like for very long, and the knife won't cut much when this happens.
Click to expand...

440A is a fairly coarse steel (carbide wise) and both of those are usually WAY soft by manufacturers as they are delegated to "tough" knives. These two combined is a recipe for poor edge holding, especially in regards to high sharpness. Benchmade is running AUS-8 at slightly above 60 HRC which should be an interesting comparison.

I compromise by leaving the edge fairly coarse, to where it cuts paper but barely shaves, then the knife remains usable for much longer.
Click to expand...

That is usually the optimal solution exactly.

-Cliff
 
I just learned that that is how Sal Glesser discovered that the steel in the Byrd line wasn't 440c. It was RC testing at around 60, but the steel wasn't brittle. So they analyzed it, and found that the chemical composition was different than 440c, and the steel was called 8cr13mov.

Very interesting bit of information!
 
You must log in or register to reply here.
Back
Top